Method of and apparatus for feeding molten glass



Aug 6 1935 E. c. STEWART 2,010,334

vME'I'IIOD-OF AND APPARATUS FOR FEEDING MOLTEN GLASS Filed April 18, 1933 Patented Aug. 6, 1935 UNITED STATES PATENT OFFICE METHOD F AND APPARATUS FOR FEEDING MOLTEN GLASS Edward C. Stewart, Washington, Pa., assgnor to Tygart Valley Glass Company, Washington,

Pa., a corporation of West Virginia Application April 18, 1933, Serial No. 666,687

4 Claims.

charges by causing a stream of molten glass to flow from the discharge orifice of a furnace boot or forehearth, the mold charges being cut from the glass as it emerges from the discharge orifice of the boot. In-some systems, the flow of glass from the orifice is periodically accelerated and retarded by various devices, such as reciprocating plungers and air pressure and suction.

In all instances, the problem of shear marks is met with, such shear marks causing irregularlyshaped chilled protrusions at the ends of the mold charges, and nally appearing as imperfections in the finished ware.

The retarding forces referred to which may be applied to the glass above the orifice by lifting of the plunger or the application of vacuum are sometimes employed not only to slightly delay the flow during shearing, but to form what is termed a suspended mold charge that may be caused to assume various shapes. If enough suction or vacuum is applied, the lower end of the stream bearing the shear mark will be drawn into the orice to effect incorporation thereof with the hotter glass.

Attempts have been made to also eliminate shear marks, by retar-ding the stream flow and applying a heating flame to the lower end of the glass below the orifice. Again, shaping cups have been provided into which the shear charge drops, and in some instances the cups are heated to prevent too great chilling of the glass.

While the dropping of a shear charge into a cup may have some tendency to push the protruding shear mark into the body of the mold charge, there is a tendency toward the folding over or lapping back of the sheared edge or protrusion at the lower end of the mol-d charge, and there is, of course, some chilling of the charge, so that the shear mark does not become properly incorpo-A rated'in and softened by the body of glass composing the charge.

The older practices above-referred to not only fail to cause proper assimilation of the shear marks in the mold charges, but required a somewhat slower mode of operation than in the case of my invention.

One object of my invention is to provide a means and a method for cutting mold charges from a freely flowing stream of glass, without the necessity of periodically retarding such fiow.

Another object of my invention is to provide a means and a method for forming properly-shaped mold charges Without the necessity of using shaping cups or the employment of the suspendedcharge method of feeding.

Still another object of my invention is to provide an improved means for eliminating shear marks at both the lower and the upper ends of a mold charge.

Some of the ways in which my invention may be practised are shown in the accompanying drawing wherein Figure l is a sectional View through a portion of a furnace boot with my apparatus in place; Fig. 2 is a sectional plan View of the apparatus of Fig. l; Fig. 3 is an inverted plan View, showing the shape imparted to the lower en-d of a molten glass stream by shears of the scissors type; Fig. 4 is an enlarged View, showing a mold charge at the time of shearing, and the manner in which shear marks at the lower end of the charge are eliminated; Fig. 5 is a View similar to Fig. 4, but showing the presser members at a different position of adjustment; Fig. 6 shows means for eliminating shear marks formed by shears of the V or shtail type, and Fig. 7 shows said means in operative position with respect to the mold charge.

Referring rst to Figs. 1 to 4, the furnace boot or forehearth is represented by the numeral 8 and a stopper or valve by the numeral 9. A flow ring or orifice bushing I0 is detachably mounted in the bottom of the boot, and can be replaced by other flow rings having orifices of different diameters than that shown in the ring I0.

cating plunger type.

'Ihe glass as it issues from the orice will gradually assume a shape departing from its cylindrical or other uniform cross section; thus, as shown in Fig. 4, the glass above the shear line is of approximately uniform cross section, but as it continues to flow, it will elongate and tend to contract somewhat.

In the forming of smaller charges of glass, I may shear the stream While it is still of approximately cylindrical form as shown in Fig. 6. Where the glass is permitted to flow for a longer period of time between shear operations, it will assume the shape shown in Fig. 4.

In that event, I may shear either at the tracted portion or at the shear line A, somewhat above the contracted area of the glass.

This

lll

shearing is preferably effected close to the orice so as to be in the hotter portions of the glass, with the result that the shear mark on the upper end or" a chargewill settle and tend to be incorporated in and melted by the glass.

The shear ma r at the lower end of a charge will be of a shape determined by the type of shears used. Thus ii shears oi the straight blade or scissors type be employed, the irregularity resulting from shearing will be of what is sometimes called the pillovy type, as shown in Fig. 3, while with shears of the shtail or l! type, the shear niark will appear in the form oi a pointed stub, as in lelie. '3. In either case, there are irregular protrusions at the lower end or .lower corners of the mold charge, which should be eliminated in order to avoid thei: appearing as imperfections in the iinished ware. An important feature oi my invention resides in the pushing oi these ragged. or irregular protrusions into the body oi the mold charge before the charge enters shaping cup or a mold.

in l and 2, l show shears oi the scissors tpe that are mounted upon a bracket plate l2 disposed beneath the boot 8. The shear blades l@ are mounted upon a pivot pin ill, and have connection through togg e linlrs i 5 with an operating lever i6. The operating lever is pivoted at ll i tothe bracket i2 and carries a roller l t that is yieldably maintained in contact with a cam disc i9 that is keyed to shaft As the shat rotates, the lever i@ is oscillated by the carri l@ to close and open the shear blades The brachet l2 is adjustable vertically in order to position the shear blades at a desired distance belovf the orifice l0.

A earn disc 22 is also secured to the shaft 2@ and through a roller 23 and a push rod 2G operates a pair of arms 25 and which carry presser members 2l. The presser members are adjustable on their arms to various angles, by means of attaching bolts Ela, so that they can properly engage the protruding corners B of the mold charge and push said corners into the mass of glass, as shown in Fig. e. The angularity of the presser members wi11,of course, be determined by the direction in which the said protrusions extend, in order to prevent folding thereof and to cause them to be pushed directly into the mass of glass.

The arms 2e' and 2t are pivotally mounted on studs or pins 2Q that are supported by the bracket l 2, and havev segmental gears incorporated therein, so that oscillation oi the arm by a push rod it will cause oscillatpn ofthe arm 25 also. A spring 3l serves to maintain the camrroller 23 in engagement with the cam disc 222. The arms E25-EG and the earn 22 are adjustable axially of the pins 2Q and shaft 2li, respectively, so as to effect the desired positioning or" the presser members Ell.

The cam discs Il@ and 22 are adjustable about the axis ci the shaft 2li, so that the shears and the shaping members will be operated in a desired timed relation. "t will be understood that the shears and the presser members can be operated by means other than cams. For example, they may be operated by air cylinders in a manner similar to that shown in my application, Serial.

As shown in the drawing, the presser members 2l may suitably be operated at approximately the instant that the shear blades close, but, of course, can be caused to engage the glass :filed August 25, 1932 (Patent No.

and become heated quickly, the danger of chilling the glass by Contact therewith will be reduced.

shap- The shear charge can be dropped into a ing cup or directly into mold.

The shear niarlss at the upper en charges are not so troubl ome, Close to the orirlce, in a tlv' L absorbed by the body or charge.

The'impac of the mold charge vfv into a or into a shaping cup will settling of the shear upper 'end of the charge in'L chrge, and tl-L's would l walls of the cup or tical or inclined.

d ipovthe mold charge that would eiieet t; e .iz I of the shear maris into the glass in sornevf"o t the saine manner as though the bott` of the l initially engaged the bottom of the cup mold.

The retardent action to downward movement of the glass charge, whether in temporary' eceiving or shaping cups, or in. the mold nous will, through settling of the thickened portion of the glass charge at the shear line cause swelling out of the contracted portion of the charge.

However, this latter feature will not be desirable in all cases, but will depend upon the shape of the mold, andconsequently the shape of the article to be formed therein. ln some cases, l will prefer to have the glass charge slightly contracted near its upper end, and in that instance, will not permit it to fall such distance that there will be material swelling out of the said reduced portion.

Referring now to Figs. 6 and 7, I show a shear maris C of the stub end type which is produced by i! type shear blades, such as those shown in my said application. The charge may be sheared from a stream having the forro shown in Fig. 6, or at a later period, after the glass has assumed somewhat the shape shown in Fig. 4.

En any event, at the time of shearing, or even before the glass reaches shearing position, a presser member 33 is swung upwardly to push the stub C into the mass of glass, as shown in Fig. 7. The presser 33 is mounted on one am of a pivotally-supported bell crank Sil, the ot er arrn of the bell crank being connected to a linku 35 which is connected to the piston of operating cylinder 3G, to which fluid pressure is n@ DJ admitted alternately, at opposite ends, in timed relation to the movement oi the shears.

it will be understood, of course, that a mold table may be mounted beneath the feeding devices, and operated so as to present a mold in position to receive a mold charge upon each operation of the shear.

From the foregoing it will loe seen that l not only provide a method whereby mold charges can be properly formed from a freely ilovving 75 stream of glass, but I provide an improved manner of eliminating the shear marks of mold glass. A

3. Apparatus for dividing a downwardly owing charges formed by other feeding methods.

I claim as myinventioml'. The method which comprises creating a downwardly owing stream of molten glass, shearing said stream of glass to form successive mold charges, and simultaneously with the shearing thereof momentarily imparting pressure against shear-marked portions of the glass at the lower end of each charge in a direction to eifect incorporation thereof into the body of the charge.

The method which comprises creating a downwardly flowing shearing said stream of glass to form successive mold charges, and simultaneously with the shearing thereof imparting pressure against shear-marked portions of the glass at the lower end of each charge in a direction to effect incorporation thereof into the body of the charge, the duration of pressure being substantially stream of molten glass,.

equal to the time required for severing of the stream of glass into mold charges, comprising a shear device operable to cut the stream into sections, and presser members periodically movable toward.l the path of glass travel, from opposite sides thereof, to press irregularities adjacent to the lower ends of the charges into the bodies i thereof, the said presser members being tiltably adjustable relative to the axis of the glass stream.

4. The method which comprises creating a downwardly flowing stream of molten glass, shearing said stream of glass to form successive mold charges, and simultaneously with the shearing thereof momentarily imparting pressure against shear-marked portions of the glass at the lower end of each charge in a direction toward and perpendicular to the adjacent surface of the mold charge. f

EDWARD C. STEWART. 

